fs/buffer.c:nobh_write_end(): NULL dereference

[Adrian Bunk <bunk@kernel.org>]

Commit 03158cd7eb3374843de68421142ca5900df845d9 introcduced the 
following NULL dereference:

<--  snip  -->

...
int nobh_write_end(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned copied,
                        struct page *page, void *fsdata)
{
        struct inode *inode = page->mapping->host;
        struct buffer_head *head = NULL;
        struct buffer_head *bh;

        if (!PageMappedToDisk(page)) {
                if (unlikely(copied < len) && !page_has_buffers(page))
                        attach_nobh_buffers(page, head);
...                                               ^^^^

<--  snip  -->

Spotted by the Coverity checker.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed